Washing machines

ABSTRACT

A washer/drier with a new pump arrangement. In the new arrangement a first pump is adapted to pump washing liquid to the treatment chamber, and a second pump is provided which is adapted to pump water through a venturi vacuum forming device for establishing below ambient pressure in the treatment chamber, typically during a spin-drying cycle. The second pump can be operated selectively to pump water to the treatment chamber for rinsing articles therein or to supply water to the venturi vacuum forming device. The treatment chamber comprises an elliptical drum having perforated wall regions at opposite internal ends thereof to the rear of which liquid is supplied or through which it is drawn out from during washing and rinsing, and through which air is drawn during the drying cycle.

FIELD OF INVENTION

[0001] This invention concerns machines for washing and drying articles and dry cleaning, particularly but not exclusively clothes, bed-linen, curtains, towels, and the like. Articles which can be washed/dried will hereinafter be referred to simply as articles.

BACKGROUND TO THE INVENTION

[0002] An improved machine for washing and drying articles is described in GB Patent Specification 2,348,213. This invention concerns certain improvements and modifications to the type of machine described therein, and a washing and drying machine such as described in GB Patent Specification 2,348,213 will be referred to herein as a washer/drier of the type described.

SUMMARY OF THE INVENTION

[0003] According to one aspect of the present invention in a washer/drier of the type described, there is provided a first pump which is adapted to pump washing liquid to the treatment chamber, and a second pump which is selectively adapted to pump water through a venturi vacuum forming device for establishing below ambient pressure in the treatment chamber for removing washing and rinsing liquids from the chamber and to assist in drying articles therein.

[0004] According to a related aspect of the present invention in a washer/drier of the type described, first pipe means is provided to deliver liquid to the treatment chamber for washing articles therein and second separate pipe means is provided for conveying rinsing water to the treatment chamber, and the first pump operates to pump liquid along the first pipe means for washing the articles in the treatment chamber, and the second pump operates selectively to pump clean water along the second pipe means for rinsing the articles in the treatment chamber or to supply water to a venturi vacuum pump.

[0005] In GB Patent Specification 2,348,213 the treatment chamber depicted in FIG. 17 of that Specification comprises an elliptical drum having perforated plates at opposite internal ends thereof through which air or water is drawn out of the drum after rinsing, and during the drying cycle.

[0006] According to another aspect of the present invention in a washer/drier of the type described, an inner shell may be provided within the elliptical drum and spaced from the solid outer drum wall to form a cavity or void therebetween, having perforations in at least two diametrically opposite regions thereof. The perforations allow water to pass from the interior of the drum into the cavity or void between the shell and the drum wall, from where it can be pumped during rinsing. They also allow water and washing liquid supplied to the cavity or void to pass into the drum and allow a venturi pump which communicates with the cavity or void to withdraw air from the drum during a vacuum assisted drying cycle.

[0007] In a preferred design the inner shell is perforated over the whole of its surface.

[0008] According to another aspect of the invention, the drum may be formed from two parallel generally elliptical flat side panels, spaced apart by and joined to opposite parallel edges of an outer wall of sheet metal, bent to conform to the generally elliptical shape of the panels, and two panels of perforated sheet metal are fitted to and extend internally across the curved end regions of the elliptical drum between the two parallel side panels, to define internal voids at opposite ends of the elliptical drum. Liquids or air can pass through the perforations to leave or enter the interior of the drum.

[0009] According to a preferred feature of the present invention a passage for communicating the or each void with the an external pump, may be formed by means of an inner plate welded or otherwise bonded to the internal face of one of the flat side walls of the drum, with a central region thereof deformed to create a reservoir and with an elongate ridge in the plate extending on opposite sides of the reservoir formation, so that when the plate is fitted flush to the flat inside surface of the drum wall, the ridge creates ducts between the reservoir and opposite ends of the drum (through which liquid or air can pass) and a central circular opening is provided in the side wall of the drum which communicates with a stationary coaxial tube to provide a fluid path from the reservoir to a pump, a rotary seal is provided between the tube and the opening, and the ducts communicate between the reservoir and the spaces behind the perforated inner wall at opposite ends of the drum.

[0010] According to a further aspect of the present invention the drum is located within a housing, with the two flat sides spaced from the front and back panels of the housing, the front housing wall includes an access opening, and the flat side wall of the drum at the front of the housing includes a large circular opening which registers with the access opening in the housing wall to enable articles to be passed axially into and out of the drum, a support frame is provided for rotatably supporting the drum in the housing, and the drum opening includes an axially extending peripheral lip which protrudes axially through a circular opening in the support frame which also registers with the access opening, and a radial bearing is secured within the opening in the support frame, with its outer race secured to the support frame and the inner race secured to the lip around the opening in the drum, to rotatably support the drum in the support frame.

[0011] Preferably a door is hinged to the housing, or the support frame, for closing the access opening.

[0012] Preferably the lip protrudes axially beyond the bearing to provide a cylindrical seating for a first annular seal, and a second annular seal co-operates with the inside of the door, the two seals serving to seal the interior of the drum. Preferably the first seal resists the passage of air or liquid from the drum and the second seal resists the passage of air in a reverse direction, into the drum, when vacuum is applied to the interior of the drum to assist drying.

[0013] In an alternative form of construction of the drum, an opening is provided in one of its curved ends, and an opening in the housing registers with the opening in the drum at one rotational position of the latter, to allow access to the drum, and the opening in the drum is sealable to retain liquid in the drum for washing and rinsing when it is rotated, and the opening in the housing is closed by a conventional door.

[0014] The drum is preferably rotated about an axis midway between the two geometric centres of the elliptical shape and where the casing is a rectilinear cabinet the access opening is preferably in the upper face of the casing. A sensing means and drum braking means may be provided so as always to stop the drum in a position in which the drum opening aligns with the access opening in the top of the housing so that articles can be inserted or withdrawn from above. Such a machine is called top loading machine.

[0015] If it is sufficient to spin the articles until they are damp-dry, the pump employed for pumping water to the vacuum forming venturi pump during the vacuum assisted spin-drying cycle need only be capable of delivering water at a pressure of 70-100 psi. Typically this will achieve a venturi vacuum of 25-26 inches of mercury, which is sufficient for removing the rinse water and the water removed by centrifugal force during the spin-dry cycle. This reduces energy requirements and therefore the cost relative to known washing machines.

[0016] In operation, a drum constructed as aforesaid will be rotated at speeds of between 50 and 2000 rpm during washing and drying cycles—the higher speeds normally applying to the spin-drying cycle when the articles are dried by centrifugal force.

[0017] If only the reduced vacuum (i.e. 25-26 inches of mercury) is applied during drying, a typical domestic wash and spin dry will take 9-13 minutes for coloureds, and up to 15 minutes if the articles are whites and are to be boiled.

[0018] If a full vacuum assisted drying cycle is included the same load will wash and dry in 15-19 minutes for coloureds, and up to 21 minutes if the articles are white and are to be boiled.

[0019] Complete drying of a typical domestic washing machine load can be achieved by supplying water to a venturi vacuum pump, at a pressure of at least 170 psi and if complete drying is required the pump must be selected accordingly. Typically a pump delivering water at 170 psi will produce a vacuum of 29 inches of mercury or above.

[0020] A washer/drier embodying the different aspects of the invention will now be described by way of example with reference to the accompanying drawings in which:

[0021]FIG. 1 is a schematic showing the pipework, valves, pumps and gauges of the washing and drying machine containing two pumps;

[0022]FIG. 2 is a perspective view from the front of a drum constructed in accordance with one aspect of the invention;

[0023]FIG. 3 is a perspective view of the rear of the drum of FIG. 2;

[0024]FIG. 4 is a perspective view from the front of another more preferred form of construction of drum, the rear view of which would be similar to FIG. 3;

[0025]FIG. 5 is a side elevation showing a drum such as shown in FIG. 4 mounted in a support frame;

[0026]FIG. 6 is an enlarged section through the open front end of the drum and support frame showing detail of how the door is mounted and sealed;

[0027]FIG. 7 is a section through the rear of the drum showing the inlet and associated passages for drawing air/liquid from the drum under vacuum; and

[0028]FIG. 8 is a cross section through a modified form of the drum construction of FIG. 4, adapted to be used in a top loading cabinet;

[0029] In the drawings all the valves are assumed to be solenoid operated.

[0030] In FIG. 1 with valves 10 and 12 closed and 14 open, cold water from a cold water feed 15 is supplied to a calorifier 16 containing an electric heating element 17, to be heated.

[0031] If valves 14 and 10 are shut and 12 is opened, cold water is instead directed to a manifold 18 associated with, and fitted to the rear central region of drum 19. The manifold 18 communicates with the interior of the drum via a passage which will be described in more detail with reference to FIGS. 2 and 4.

[0032] With vales 12 and 14 closed and 10 open, cold water flows into reservoir 20 to top up the level of water therein. The reservoir provides a supply of water for the pump 22 which is driven by motor 24, by belt 23.

[0033] The pump 22 supplies cold water from 20 to a venturi pump unit 26, the vacuum side of which communicates with the manifold 18 when valve 32 is open. Provided all the other valves linked to the manifold 18 are closed, the action of the venturi pump will be to draw air and water/water vapour out of the drum 19 via the manifold 18, and this becomes entrained in the water which is passing at high velocity through the venturi to exit via pipe 27 as a return feed to reservoir 20. The water in 20 is thereby largely recirculated and added to by any water collected from the drum interior. To this end, if valve 32 is open it is important that all of valves 34-40 are closed.

[0034] When opened, valve 34 allows the internal pressure in the drum to be shown on gauge 42.

[0035] Drying can be speeded up by using warmed air or other heating methods. To this end a fan heater 44 heats air drawn in via an opening 45 and forces the heated air via pipe 46 and valve 38 into the manifold 18, from where it is conveyed into the interior of the drum 19. An interlock is provided to prevent 44 from operating if 38 is not fully open.

[0036] In a preferred mode of operation, 44 and 22 are operated intermittently so that the moisture laden air in the drum 19 is alternately heated by 44 and then drawn off the by venturi pump 26 by closing 38 and opening. The moisture-laden air drawn off is transferred via pipe 47 to reservoir 20. In this connection a vent 48 from 20 allows air to escape and excess water to overflow, since the level of water in 20 will not exceed the vent 48. It has been found that repeating this process two or three times, obtains a more efficient drying step than otherwise is the case.

[0037] If a hot water supply feed is available this can be used—but is not essential.

[0038] If hot water is available valve 49 can be opened to admit hot water into reservoir 50 to raise the temperature of the water in the calorifier 16. This shortens the water-heating step linked to immersion heater 17, and if hot enough, can eliminate the need for 17 to be operated.

[0039] If hot water is available it is useful to use hot water for some of the rinses—especially the final rinse. This is achieved by opening 36 and closing 48.

[0040] A thermostat 52 is fitted to the calorifier 16. Thermostat 52 senses the temperature of the water in 16 and its output is directed to turn off heating element 17 and turn on pump 58 and open valve 40 to admit hot water into manifold 18, when the correct temperature is reached. A second temperature or water level sensor 54 may be employed if required.

[0041] Item 60 is a rotary joint allowing the drum 19 to rotate relative to the manifold 18.

[0042] The front of drum 19 of FIG. 1 is shown in FIG. 2. The large circular opening 62 allows articles to be loaded and unloaded. The front and rear walls are formed from two similar generally elliptical plates 64, 66 and the boundary wall is formed by two flat plates 68, 70 and two curved ends 72, 74. Items 68, 70, 72 and 74 may be formed by bending a single length of sheet metal if desired.

[0043] The ends 64, 66 are welded or bonded or otherwise joined to the edges of the boundary wall 68, 70, 72, 74.

[0044] As best shown in FIG. 3 a smaller opening 76 is provided in a central annular housing 78 in which a bearing can be fitted for mounting the rear of the drum for rotation.

[0045] At the front end an annular rim 80 extends axially around the opening 62 to be supported by the inner race of a second, larger diameter bearing (see FIG. 7). The axis of the bearing in 76 is co-axial with that around 80.

[0046] By providing an axial passage through the bearing (not shown) fitted in 76, water and air can be introduced into the drum or withdrawn therefrom.

[0047] Since it is better for this to occur from regions near the perimeter of the drum interior, passages are formed from the central region of wall 66 to the two curved ends, one of which is shown at 82. These are most simply formed by folds or ridges in sheet metal which create elongate passages leading from a cylindrical cup shaped housing around the internal end of the bearing (not shown) in opening 76. The outboard ends of the passages (one of which is denoted by reference numeral 82) communicate with voids behind flat perforated plates such as 84. Alternatively if the end wall of the drum is stiffened by radial bracing, some or all of the stiffening members may be formed from hollow section bar, the hollow interior(s) providing the passages to the central region of the drum.

[0048] The preferred design shown in FIG. 4 provides for an internal shell, designated 86, similar in shape, but all round slightly smaller than the outer drum 19. The inner shell 86 is perforated over some or all of its surface and water and/or air is conveyed to and from the interior of the drum through the perforations. One or more passages, such as 82 described with reference to FIG. 2 serves to communicate the void behind the inner shell 86 with the pump(s) for pumping fluid to or from the drum.

[0049] The internal shell is most simply held in place by for example welding or brazing its edges to the inside faces of the two end plates 64 and 66.

[0050] In the two views of FIGS. 5 and 6 a bearing 88 is shown surrounding the rim 80 of the drum 19. Two annular seals are shown. Seal 90 serves to prevent air or water escaping when the interior of the drum is under positive pressure. Seal 92 serves to prevent the ingress of air into the drum when the interior of the drum is subject to negative pressure/vacuum.

[0051] A door 94 with viewing window 96 is hinged to a support frame 98 at 100. A catch 102 is provided on the opposite side. Seal 92 is crushed between the door and the other seal 90.

[0052] The thin metal wall of the box-like casing within which the drum and support frame, motors, pumps, reservoir, valves and pipework are located, is denoted by reference numeral 104.

[0053]FIG. 7 shows how the drum design can be modified by providing a porthole opening 106 at one end with sealable closure 108. This allows the drum to be rotated about the same axis as before, this time being carried by two similar small bearings, as the large access opening 62 is no longer required. To this end stub-shaft extensions to the drum are shown in FIG. 7 at 109, 111. An internal perforated wall shell 110 is similarly located within the drum, and the void between it and the drum communicates with a stationary pipe 112, via a rotary joint, through stub shaft 111.

[0054] In FIG. 7 a domed end 77 of a cylindrical housing protrudes through the rear wall of the drum of FIGS. 2 and 3 to form externally of the drum the annular housing 78 shown in FIG. 3. Two tubes 84, 85 are shown communicating between the interior of the reservoir formed by the domed end 77 and the region(s) behind the perforated plates(s) 84 of FIG. 2 or the perforated inner drum wall 86 of FIG. 4. The tubes 83, 85 extend internally within the domed end 77 of the housing, to form a T-junction 87 (shown dotted).

[0055] A tube 76 (also shown dotted in FIG. 7) comprises the other part of the T-junction and extends axially of the drum for connection to the suction pump 26 (of Fig ?).

[0056] A bearing (not shown) may be arranged between the tube 76 and the housing 78 or instead around the latter.

[0057] The tube 76 will obviously rotate with the drum, and to this end a sealed bearing (not shown) is provided between the tube 76 and a stationary extension tube (not shown) to allow for this rotation and for the extension tube to connect to the vacuum pump 26. A further bearing (not shown) may be provided between the tube 76 and the stationary housing within which the drum is mounted (or where the drum is carried by a support frame 98 between the tube 76 and the frame 98). 

1. A washer/drier of the type described, in which there is provided a first pump which is adapted to pump washing liquid to the treatment chamber, and a second pump which is adapted to pump water through a venturi vacuum forming device for establishing below ambient pressure in the treatment chamber during a spin-drying cycle.
 2. A washer/drier as claimed in claim 1, wherein the second pump operates selectively to pump water to the treatment chamber for rinsing articles therein or to supply water to the venturi vacuum forming device.
 3. A washer/drier of the type described or as claimed in claim 1 or 2, wherein the treatment chamber comprises an elliptical drum having perforated wall regions at opposite internal ends thereof to form cavities or voids to which liquid is supplied or drawn out from during washing and rinsing, and through which air is drawn during the drying cycle.
 4. A washer/drier of the type described or as claimed in claim 1 or 2, wherein an inner shell is provided within the elliptical drum spaced from the solid outer drum wall to form a continuous cavity or void around the drum, and perforations are provided in diametrically opposite regions of the inner shell.
 5. A washer/drier as claimed in claim 4 wherein liquid is pumped to the cavity or void under pressure so as to be forced into the drum through the perforations.
 6. A washer/drier as claimed in claim 3, 4, or 5 wherein a venturi vacuum forming device communicates with the or each cavity or void to withdraw air from the drum during a vacuum assisted drying cycle.
 7. A washer/drier as claimed in any of claims 4 to 6 wherein the inner shell is perforated over the whole of its surface.
 8. A washer/drier as claimed in claim 3 or 4 wherein the drum is formed from two parallel generally elliptical flat side panels, spaced apart by and joined to opposite parallel edges of an outer wall of sheet metal, bent to conform to the generally elliptical shape of the panels, and two panels of perforated sheet metal are fitted to and extend internally across the curved end regions of the elliptical drum between the two parallel side panels, to define internal voids at opposite ends of the elliptical drum, or an inner metal sheet shaped to conform to the outer wall but spaced internally therefrom to define a continuous void therebetween, is provided, with perforations at least in the end regions.
 9. A washer/drier as claimed in claim 8 wherein a passage for communicating with the or each void is formed by means of an inner plate welded or otherwise bonded to the internal face of one of the flat side walls of the drum, and a central region thereof is deformed to create a reservoir, and an elongate ridge is formed in the plate which extends on opposite sides of the reservoir formation, so that with the plate fitted flush to the flat inside surface of the drum wall, the ridge creates ducts between the reservoir and opposite ends of the drum through which fluid can pass.
 10. A washer/drier as claimed in claim 9 wherein a central circular opening is provided in the side wall of the drum which communicates with a co-axial tube to provide a fluid path from the reservoir.
 11. A washer/drier as claimed in claim 10 wherein a rotary seal is provided between the tube and the opening to allow for relative movement therebetween.
 12. A washer/drier as claimed in claim 11 wherein the ducts communicate between the reservoir and the spaces behind the perforations at opposite ends of the drum.
 13. A washer/drier as claimed in any of claims 3 to 12 wherein the drum is located within a housing, with the two flat sides of the drum spaced from front and back walls of the housing, the front housing wall includes an access opening, and the flat side wall of the drum at the front of the housing includes a large circular opening which registers with the access opening in the housing wall to enable articles to be passed axially into and out of the drum.
 14. A washer/drier as claimed in claim 13 further comprising a support frame for rotatably supporting the drum in the housing, and the drum opening includes an axially extending peripheral lip which protrudes axially through a circular opening in the support frame which also registers with the access opening, and a radial bearing is secured within the opening in the support frame, with its outer race secured to the support frame and the inner race secured to the lip around the opening in the drum, to rotatably support the drum in the support frame.
 15. A washer/drier as claimed in claim 13 or 14 wherein a door is hinged to the housing, for closing the access opening.
 16. A washer/drier as claimed in claim 15 wherein two annular seals are provided, a first of which resists the passage of air or liquid from the drum and the second of which resists the passage of air into the drum when the pressure in the drumis reduced below atmospheric.
 17. A washer/drier as claimed in claim 16 in so far as it is dependent from claim 14 wherein the lip protrudes axially beyond the bearing to provide a cylindrical seating for one of the annular seals, and the other annular seal co-operates with the inside of the door.
 18. A washer/drier of the type described or as claimed in claim 1 or claim 2 wherein the treatment chamber is an elliptical drum rotatably mounted in the housing, an opening is provided in one of its curved ends and another opening is provided in the housing, which registers with the opening in the drum at one rotational position of the latter, to allow access to the interior of the drum, and the opening in the drum is sealable to retain liquid in the drum for washing and rinsing when it is rotated, and the opening in the housing is closed by a conventional door.
 19. A washer/drier as claimed in claim 18 wherein the drum is rotated about a horizontal axis midway between the two geometric centres of its elliptical shape the housing is a rectilinear cabinet, and the access opening is in the upper face of the housing.
 20. A washer/drier as claimed in claim 19 wherein sensing means and braking means is provided, so as always to stop the drum in a position in which the opening therein aligns with the access opening in the housing, so that articles can be inserted or withdrawn from above.
 21. A washer/drier as claimed in any of claims 1 to 20 wherein the pump employed for pumping water to the vacuum forming venturi pump during the vacuum assisted spin-drying cycle is capable of delivering water at a pressure of 70-100 psi, so as to achieve a venturi vacuum of 25-26 inches of mercury.
 22. A washer/drier as claimed in any of claims 1 to 20 wherein the pump employed to supply water to the venturi vacuum pump supplies the water thereto at a pressure of at least 170 psi so as to produce a vacuum of the order of 29 inches of mercury.
 23. A washer/drier as claimed in any of claims 1 to 22 wherein the drum is rotated at speeds of the order of 50 rpm during washing and up to 2000 rpm during spin-drying cycles. 